Updraft: March 22, 2011 Archive

Duluth: Blizzard... Metro: Rain & thunder, then snow

Posted at 12:15 AM on March 22, 2011 by Paul Huttner
Filed under: Crow River, Flooding, Minnesota River, Mississippi River, Winter storms, Winter/spring 2011

Update 12:15 am:

Radars show bands of showers and embedded T-Storms moving northeast through southern Minnesota. Expect heavy rain, lightning and thunder, and possible hail as the storms move through early this Tuesday morning.

The late model runs are cranking out an incredible 1.84" liquid precip for the Twin Cities with this storm. Most will fall as rain Tuesday, but indications are about .41" could fall as wet snow Wednesday. That could translate into 2" to 4" of wet slushy snow by late Wednesday in the metro.

Late night NAM Cobb method yields 2" to 4" snowfall totals for Metro Wednesday. (Click to enlarge)

Stay tuned.

-Latest Twin Cities radar loop

PH

***Original post 5:35pm Monday***

After a pretty quiet month, the March Lion is set to roar.

A hybrid winter/spring storm looks like it will roar the loudest from North Dakota through northern and central Minnesota into northern Wisconsin. A combination of heavy snow and wind Tuesday night and Wednesday will slam cities and towns including Grand Forks, Fargo, Bemidji, Brainerd, Duluth, Hinckley, Hayward and Rice Lake.

Winter storm warnings are flying for North Dakota, central and northern Minnesota, and northern Wisconsin. Blizzard warnings have been hoisted for Duluth and the North Shore.

The system:

Low pressure is spinning out of the Rockies headed for the Upper Midwest Tuesday. This a good track to bring heavy precip to Minnesota.

Low track across Iowa. (Click to enlarge all graphics)

Thermal profile:

The storm is forecast to track east through Iowa. Milder air with this hybrid winter/spring system will mean the initial waves of precip Tuesday will be mostly rain. As colder air filters in Tuesday night & Wednesday, precip will change over to snow from north to south.

It looks like most of the precip will fall as snow in Brainerd and Duluth (mixing with rain to start), and most will fall as rain ending with some wet snow in the metro.

Timing:

Expect waves of rain to move in after midnight into Tuesday morning and continue on and off as the changeover to snow occurs Tuesday night into Wednesday from north to south.

Thunder?

There could be enough rising air, what meteorologists like to call "upward vertical velocity"... to produce a few thunderstorms Tuesday, especially afternoon & evening.

Severe risk?

SPC has included southwest Minnesota in a slight risk for severe weather. This is the first time this year any part of Minnesota has been included in a severe risk area.

Welcome to spring.

Rain & Snowfall totals:

The system should deliver widespread rain to southern Minnesota and heavy snow up north.

The NAM model is cranking out as much as 1'+ for the metro and points north.

The band of heaviest snow appears to be setting up from Fargo through Brainerd to Duluth. It looks like 6" to 12" of wet wind driven snow may fall in the heavy snow band. Areas around Duluth could see 12"+!

At this point, I think 1" to 3" of wet slushy snow could fall in the metro Wednesday. The best chance fo 3" will be in the norhtern suburbs.

Flood impacts:

An inch or more of rainfall will have an impact on rising rivers. NWS Hydrology has factored this in to the latest set of river forecasts Monday, and the latest forecasts are here.

Overall most river forecasts were raised between 1 and 2 feet later this week into the weekend.

Stay tuned as our next storm moves into Minnesota.

PH

Bad to worse: Heavy rain triggers rapid river rises

Posted at 9:44 AM on March 22, 2011 by Paul Huttner (1 Comments)
Filed under: Crow River, Flooding, Minnesota River, Mississippi River, Winter/spring 2011

Here we go again, and the timing couldn't have been worse.

The "nightmare scenario" for flood forecasters and river residents is in progress in southern Minnesota. The last thing you want to see as rivers rise is a shot of heavy rain, but that's exactly what we're getting today.

****Flood warnings are in effect for most all area rivers and creeks in southern Minnesota. If you live near a river that is expected to flood this week, all necessary preparations should be rushed to completion today. This is a serious situation, and major to near record flood levels may be observed in the next week.****

-Latest flood warnings here!

Our hybrid late winter-early spring storm is delivering widespread rain with embedded heavy rain. The rain is effectively washing much of the remaining snow cover away into rivers and streams, providing a sort of "shock" or turbo boost to runoff and raising river levels more rapidly in the process.

458 AM CDT TUE MAR 22 2011

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* FLOOD WARNING FOR RAIN AND MELTING SNOW IN...
CHIPPEWA COUNTY IN WEST CENTRAL MINNESOTA...
KANDIYOHI COUNTY IN CENTRAL MINNESOTA...
LAC QUI PARLE COUNTY IN WEST CENTRAL MINNESOTA...
MCLEOD COUNTY IN CENTRAL MINNESOTA...
MEEKER COUNTY IN CENTRAL MINNESOTA...
RENVILLE COUNTY IN CENTRAL MINNESOTA...
WRIGHT COUNTY IN CENTRAL MINNESOTA...
YELLOW MEDICINE COUNTY IN WEST CENTRAL MINNESOTA...

* UNTIL 500 PM CDT WEDNESDAY

* AT 445 AM CDT...SEVERAL ROUNDS OF HEAVY RAINFALL OVERNIGHT...PLUS
SATURATED SOILS AND THE CONTINUED THREAT OF LOCALLY HEAVY RAINFALL
WILL LEAD TO EXCESSIVE RUNOFF AND AREAL FLOODING. CREEKS AND
STREAMS ARE EXPECTED TO RISE TODAY AS A RESULT. BECAUSE ADDITIONAL
PRECIPITATION IS EXPECTED LATER TODAY AND TONIGHT...THIS WARNING
WILL BE VALID THROUGH WEDNESDAY AFTERNOON.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLOODING TO
OCCUR.

Here are some rainfall reports and totals as of early Tuesday morning:

Twin Cities Metro

CITY SKY/WX TMP DP RH WIND PRES REMARKS

TWIN CITIES LGT RAIN 36 34 93 E20G26 29.92F FOG
6HR MIN TEMP: 36; 6HR MAX TEMP: 39; 6HR PCP: 0.33;

ST PAUL LGT RAIN 36 33 89 E10G18 29.97F FOG

CRYSTAL RAIN 36 33 89 E12 N/A FOG

BLAINE HVY RAIN 36 34 93 E22G29 29.94F

EDEN PRAIRIE LGT RAIN 36 34 92 E15G25 29.90F FOG
6HR MIN TEMP: 36; 6HR MAX TEMP: 39; 6HR PCP: 0.45;

LAKEVILLE HVY RAIN 34 34 100 E15 29.89F WCI 24

As of 7:30 am the Huttner Weather Lab in Deephaven has recorded .73" of rainfall. There's an interesting note here. My tipping rain bucket is located in a spot where some melting snow form a nearby snow pile may have added to the rain total.

Here's why it may not matter...the effect of the rain washing the snow into the gauge is the same effect occurring in the landscape where snow cover is present. While my actual rainfall may have been slightly less...the "effective" rainfall and subsequent runoff of .73" is probably closer to what's occurring in the landscape as combined rainfall and snow melt washes into area streams and rivers today.

Here's a look at storm total rainfall estimates fort he Twin Cities doppler radar Tuesday morning. Note the one inch plus totals southwest of the metro, right over the Minnesota River Watershed.

Also note the heavy 2"+ totals northwest of the Metro near Big Lake, right over the Mississippi River watershed. This pretty much seals the fate for the Mississippi River, and forecasts for a potential crest next week at St. Paul continue to rise.

Smaller rivers respond with rapid rises today:

The overnight rains (and some ice jams) have already triggered measureable rises in smaller rivers today. Take a close look at the hydrographs below, and notice the river "spikes" as runoff quickly raises river levels. Also notice how the observed river levels outpace the latest river forecast trajectories for some rivers.

Mississippi level raised again:

All the extra water form the Crow, Minnehaha Creek & Minnesota River watersheds has to go somewhere, and it ends up in the Mississippi.

The latest hydrograph for the Mississippi in St. Paul raises the level of the river to 21.3 feet by Monday. This would be 3 feet higher than last year's crest of 18.38' on 3/24/10 which was the 8th highest flood of record.

This would be the 7th highest flood of record on the Mississippi at St. Paul, with a top 5 flood within reach.

Historical Crests for Mississippi River at St. Paul

(1) 26.40 ft on 04/16/1965
(2) 25.00 ft on 04/15/1969
(3) 23.76 ft on 04/18/2001
(4) 23.60 ft on 04/30/2001
(5) 22.90 ft on 04/13/1997
(6) 21.90 ft on 04/16/1952
(7) 19.65 ft on 06/26/1993
(8) 18.38 ft on 03/24/2010
(9) 17.90 ft on 04/16/1951
(10) 16.30 ft on 05/16/1986

More top 5 floods ahead?

This week's rain and snow melt may send several area rivers into "top 5" territory by this weekend or next week.

Rain to snow today into Wednesday:

The rain snow line is setting up pretty much as expected today between the metro and Duluth. As the system draws in colder air, the rain will change to snow tonight, and move south. I expect all snow in the metro by early Wednesday morning.

It still looks like the heavy snow band, and a dangerous winter storm with blizzard conditions, will set up from Brainerd to Duluth. A wind whipped 6" to 12"+ could fall in there areas by late Wednesday.

Blizzard and winter storm warnings remain in effect.

In the metro it all depends on when the snow changes over. If it's early tonight, we could see totals from 2" to 4" in the metro, heaviest north. If it's later, the 1" to 3" will be more likely.

NAM snowfall output paints heavy snow band through central Minnesota and northern Wisconsin.

Either way, expect a transition to a few inches of wet slushy snow in the metro Wednesday.

Stay tuned as we track river rises in the coming days.

PH

(1 Comments)

Rising rivers, rain, wind, snow and a blizzard

Posted at 5:29 PM on March 22, 2011 by Paul Huttner (1 Comments)
Filed under: Crow River, Flooding, Minnesota River, Mississippi River, Winter/spring 2011

Rain, thunder, floods, high winds, heavy snow, and a blizzard. Just another day in Minnesota weather. I almost have to pinch myself and ask if what I'm seeing on the weather maps is real!

Let's take them one by one.

Flood Update:

-Latest river levels and forecasts here

I spoke with hydrologist Diane Cooper this afternoon from the North Central River Forecast Center in Chanhassen. Here's the latest on how today's rains affected rivers and forecasts.

-This morning's rainfall was generally between .50" to 1" in most watersheds in southern Minnesota. That's almost twice the amount they had fed into the river forecast models in yesterday's forecast update. As a result (especially smaller) rivers rose more rapidly today. They have updated forecasts today to reflect the heavier overnight rainfall.

-NCRFC raised flood "categories" by one level for several river points. The complete text of today's latest flood warning is here.

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1206 PM CDT TUE MAR 22 2011

...FORECAST FLOODING INCREASED FROM MODERATE TO MAJOR SEVERITY...THE FLOOD WARNING CONTINUES FORTHE MINNESOTA RIVER AT MONTEVIDEO.

* FROM WEDNESDAY EVENING UNTIL FURTHER NOTICE.
* AT 11:00 AM TUESDAY THE STAGE WAS 11.8 FEET.
* MAJOR FLOODING IS FORECAST.
* FLOOD STAGE IS 14.0 FEET.
* FORECAST...RISE ABOVE FLOOD STAGE BY TOMORROW LATE EVENING AND
CONTINUE TO RISE TO NEAR 18.7 FEET BY MONDAY EARLY AFTERNOON.
ADDITIONAL RISES ARE POSSIBLE THEREAFTER.
* IMPACT...AT 18.0 FEET...SANITARY SEWERS BEGIN TO BE AFFECTED AT THIS
LEVEL.
* FLOOD HISTORY...THIS CREST COMPARES TO A PREVIOUS CREST OF 18.3 FEET
ON MAR 29 2009.

$$

...FORECAST FLOODING INCREASED FROM MODERATE TO MAJOR SEVERITY...THE FLOOD WARNING CONTINUES FOR THE MINNESOTA RIVER NEAR JORDAN.

* UNTIL FURTHER NOTICE.
* AT 11:00 AM TUESDAY THE STAGE WAS 26.9 FEET.
* MINOR FLOODING IS OCCURRING AND MAJOR FLOODING IS FORECAST.
* FLOOD STAGE IS 25.0 FEET.
* FORECAST...THE RIVER WILL CONTINUE RISING TO NEAR 34.1 FEET BY
MONDAY MORNING. ADDITIONAL RISES MAY BE POSSIBLE THEREAFTER.
* FLOOD HISTORY...THIS CREST COMPARES TO A PREVIOUS CREST OF 33.5 FEET
ON JUN 24 1993.

$$

...FORECAST FLOODING INCREASED FROM MODERATE TO MAJOR SEVERITY...THE FLOOD WARNING CONTINUES FOR THE SOUTH FORK CROW RIVER BELOW MAYER.

* UNTIL FURTHER NOTICE.
* AT 10:30 AM TUESDAY THE STAGE WAS 10.8 FEET.
* MAJOR FLOODING IS FORECAST.
* FLOOD STAGE IS 11.0 FEET.
* FORECAST...RISE ABOVE FLOOD STAGE BY LATE THIS AFTERNOON AND
CONTINUE TO RISE TO NEAR 17.3 FEET BY EARLY SATURDAY MORNING.
ADDITIONAL RISES ARE POSSIBLE THEREAFTER.
* IMPACT...AT 16.5 FEET...WATER ENCROACHING ON STATE HIGHWAY 25
BETWEEN STATE HIGHWAY 7 AND CARVER COUNTY ROAD 122.
* FLOOD HISTORY...THIS CREST COMPARES TO A PREVIOUS CREST OF 16.8 FEET
ON MAR 20 2010.

$$

...FORECAST FLOODING INCREASED FROM MODERATE TO MAJOR SEVERITY...THE FLOOD WARNING CONTINUES FOR THE CROW RIVER AT ROCKFORD.

* FROM WEDNESDAY AFTERNOON UNTIL FURTHER NOTICE.
* AT 11:00 AM TUESDAY THE STAGE WAS 8.7 FEET.
* MAJOR FLOODING IS FORECAST.
* FLOOD STAGE IS 10.0 FEET.
* FORECAST...RISE ABOVE FLOOD STAGE BY TOMORROW AFTERNOON AND
CONTINUE TO RISE TO NEAR 15.6 FEET BY SUNDAY EARLY AFTERNOON.
ADDITIONAL RISES ARE POSSIBLE THEREAFTER.
* IMPACT...AT 15.0 FEET...SANITARY SEWERS SERVING HOMES CLOSEST TO
RIVER MAY BEGIN TO BACK UP.
* FLOOD HISTORY...THIS CREST COMPARES TO A PREVIOUS CREST OF 16.1 FEET
ON JUN 26 1957.

$$

...FORECAST FLOODING INCREASED FROM MODERATE TO MAJOR SEVERITY...THE FLOOD WARNING CONTINUES FOR THE MISSISSIPPI RIVER AT RED WING.

* FROM SATURDAY AFTERNOON UNTIL FURTHER NOTICE.
* AT 7:23 AM TUESDAY THE STAGE WAS 7.0 FEET.
* MAJOR FLOODING IS FORECAST.
* FLOOD STAGE IS 14.0 FEET.
* FORECAST...RISE ABOVE FLOOD STAGE BY SATURDAY AFTERNOON AND
CONTINUE TO RISE TO NEAR 16.1 FEET BY TUESDAY MORNING. ADDITIONAL
RISES ARE POSSIBLE THEREAFTER.
* IMPACT...AT 16.0 FEET...RED WING MILLING COMPANY MAY EXPERIENCE
BASEMENT FLOODING AND BEGIN PUMPING.
* FLOOD HISTORY...THIS CREST COMPARES TO A PREVIOUS CREST OF 16.4 FEET
ON APR 17 1951.

$$

...FORECAST FLOODING INCREASED FROM MINOR TO MODERATE SEVERITY...THE FLOOD WARNING CONTINUES FOR THE REDWOOD RIVER NEAR REDWOOD FALLS.

* UNTIL FURTHER NOTICE.
* AT 10:30 AM TUESDAY THE STAGE WAS 14.5 FEET.
* MINOR FLOODING IS OCCURRING AND MODERATE FLOODING IS FORECAST.
* FLOOD STAGE IS 6.0 FEET.
* FORECAST...THE RIVER WILL CONTINUE RISING TO NEAR 15.1 FEET BY
AFTER MIDNIGHT TOMORROW THEN BEGIN FALLING.
* FLOOD HISTORY...THIS CREST COMPARES TO A PREVIOUS CREST OF 14.6 FEET
ON APR 9 1969.

$$

THE NATIONAL WEATHER SERVICE IN CHANHASSEN HAS ISSUED A

* FLOOD WARNING FOR THE ST CROIX RIVER AT STILLWATER.

* FROM SUNDAY EVENING UNTIL FURTHER NOTICE.
* AT 11:00 AM TUESDAY THE STAGE WAS 79.4 FEET.
* MODERATE FLOODING IS FORECAST.
* FLOOD STAGE IS 87.0 FEET.
* FORECAST...RISE ABOVE FLOOD STAGE BY SUNDAY EVENING AND CONTINUE TO
RISE TO NEAR 88.0 FEET BY TUESDAY MORNING. ADDITIONAL RISES ARE
POSSIBLE THEREAFTER.
* IMPACT...AT 89.0 FEET...THE CITY PARK IN BAYPORT BEGINS FLOODING.
* FLOOD HISTORY...THIS CREST COMPARES TO A PREVIOUS CREST OF 87.9 FEET
ON JUN 28 1993.

$$

-NCRFC hydrologists raised the forecast levels of the following rivers by over 1 foot today. The updated forecasts now put several river points into "top 5 flood of record" territory.

Crow @ Delano

Forecast = 21.2' this weekend. (2nd highest flood of record)

Minnesota @ New Ulm, Mankato, Henderson, Shakopee

Mississippi @ St. Paul

The latest forecast for the increasingly mighty Mississippi at St. paul is for a level of 22.4 feet by next Tuesday...and still rising. This would be the 6th highest flood of record at St. Paul, and a full 4 feet above last year's crest on 3/24/2010!

-Diane also points out that, like meteorology, flood forecasting is not an exact science. Forecasting a flood crest a week out is like forecasting a snowstorm 7 days out. We may know it's going to snow, but the science does not allow us to accurately put out a forecast of say...12.5" a week in advance.

We give a range for snowfall forecasts, and hydrologists do the same for river levels. The "number" you see on hydrographs is just the best estimate of the specific level given available data at that point in time.

Next wave of precip moving through overnight.

Part II of our current storm is ramping up in Minnesota tonight. The next wave of rain and snow is here, and it still looks like the snowfall will be heavy overnight into Wednesday through eastern North Dakota, central Minnesota and northern Wisconsin.

Winter storm and blizzard warnings continue.

Heavy snow band trending south?

There are some indications that the system's heavy snow band could shift 50 miles south overnight. This would place the southern edge of the heaviest snow closer to the northern suburbs of the Twin Cities metro, and could increase snowfall overall in the Twin Cities.

Some models are leaning toward a 2" to 4" range for the metro by late Wednesday, with the potential for 6" in the far northern suburbs.

Bottom line: Rain changing to snow overnight. Heaviest snow band with a potential of 6" to 12"+ includes Fargo-Alex-Brainerd-St. Cloud-Hinckley-Mora-Duluth-Rice Lake.

Best forecast for metro appears to be 2" to 4" at this point, with heavier totals possible north metro. Expect a snowy rush hour Wednesday morning in the metro, with winter storm to blizzard conditions to the north.

Gale warnings and big waves on Superior:

Gale warnings are in effect for Lake Superior. Webcam here.

An angry Lake Superior rages in Duluth.

Stay tuned!

PH

(1 Comments)